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What's the best way to generate gt2 gears / pulleys? I've looked around thingiverse and done some searches. I've found a program which you can buy that just design gears...

How are you guys designing gt2 gears?

This one? http://www.gearotic.com/

I use Gearotic on my CNC mil with a 4th axis to cut gears by gear shaving. It yields VERY accurate results. Not sure however how you would get a model file from it since it default output is G-Code for either shaving or 2-d cutting. A question to Art Feeney would likely be in order.

nitewatchman

It looks like for some gear types the program will output STL files. I assume these can just be sliced and output to a 3D printer. The FAQ mentions the STL output. I see from their discussion forum that a few months back they were testing Bevel gears, which is what I would be most interested in.

nitewatchman wrote:I use Gearotic on my CNC mil with a 4th axis to cut gears by gear shaving. It yields VERY accurate results. Not sure however how you would get a model file from it since it default output is G-Code for either shaving or 2-d cutting. A question to Art Feeney would likely be in order.

nitewatchman

's been a while since I used it, but I would generate the gear and output it as a dxf. file and edit it for the spokes, or features I wanted. From that I could extrude it in Autocad, or Solidworks.

Gearotic 2.0 does all kinds of neat stuff. It'll spit out STL files for anything as far as I can tell.

g.

Good to know that Gearotic will output .stl's. It is a great program!

Below are photos of Gears machined with Gearotic Code.

nutewatchman

Huh... Well this is the 3rd time replying so hopefully it'll work....

Anyway gearotic looks like just the ticket but I'm not going to get it to produce a single gear :/

Any chance I could convince you to make a drawing for me Nitewatchman? I've not used the program so I'm not sure if I'm asking a lot here.

If so, a 2d dxf is all I need.
I would like a 450mm diameter (yes that's correct) gear using the 2mm pitch gt2 standard. Intended for use with the pretty standard timing belts we use.

Also, how did you wreck your lathe?

I can sure try to make up something for you. I am traveling now but will be in this weekend. I can make something, up send you the sketch and go from there.

I am in the ongoing process of building a .22cal 10 barrel Gatling Gun. The barrels are turned full lenght to .5" diameter. Since this is a long limber cut it is done at slow speed and very light feed with a sharp tool, takes a long time for each cut. Not being very paticent, I went off to do something else and spent to much time away. The carriage wing ran into the headstock stalling the lathe, bending the pinion shaft and breaking several teeth. Fortunately the rack was not damaged. The lathe is a Tawain knockoff so geting parts is not only expensive but a real crap shoot.

nitewatchman

Cheers mate, don't worry, whenever you next get around to it!

Wow, that's a cool project! It's not 3d printing related but be sure to post some shots of it once it's done or even some of the build, this sounds very fascinating!

How many teeth would that be? And Gearotic lists GT2-5, and GT2-8.

Here's one with 284 teeth.

Well thanks Mac!

I've not had a chance to open it yet (though I was sorely tempted) my mum is visiting from the USA so we picked have hung out with her today.

I'm a gearotic user. Great program highly recommend it, well supported, regularly updated.

Mac, I opened the file on the weekend, thanks! I like the cool looking internal pattern on the gear
For some reason only 2 teeth show up on the imported .dxf though. Perhaps it's because I'm using Illustrator instead of a proper CAD program... I should be able to figure it out from these 2 teeth still, so thanks a lot!

You did better than I did,,,I generated, and uploaded that file from work. I just tried to open that at home and got nothing! Hmmm.

Here's a .pdf version of the .dfx file.

It shows all the teeth.

nitewatchman

Mac The Knife wrote:You did better than I did,,,I generated, and uploaded that file from work. I just tried to open that at home and got nothing! Hmmm.

Ha ha! Never has your signature been more relevant

Nitewatchman, thanks that does open and show all teeth.

Thanks so much to both of you - I'll show you what it's from when I get it cut and the pieces all in one place Oh no I'm doing that rotten tease thing again!

There is one potential problem to be aware of.

GT2 is the tooth profile style but it is available in several pitches. There is a 2mm pitch which is what the RMV1&2 uses and there are others like a 3mm, 5mm and 8mm. The gear in the .dfx/.pdf is a 5mm pitch. As long as all the components are the same pitch it should work find. If you are using Rostock type pats however it will not match.

You were likely aware of this already but I thought I would mention it just in case.

nitewatchman

Are you sure what you gave me was 5? The pitch is the distance between the peaks right?

All this is fairly new territory to me, so I appreciate any tips you have

nitewatchman wrote:Here's a .pdf version of the .dfx file.

It shows all the teeth.

nitewatchman

I had this issue from time to time and I am trying to remember how I solved it. It'll come to me.

(BTW your avatar just alarms me for some reason, LOL)

here it is in GT-8 profile. both .pdf, and .dxf

Flateric wrote: (BTW your avatar just alarms me for some reason, LOL)

Just a picture of a good ol southern boy.

I grew up in a region where you went to a family reunion to pick up chicks!

nitewatchman

McSlappy wrote:Are you sure what you gave me was 5? The pitch is the distance between the peaks right?

All this is fairly new territory to me, so I appreciate any tips you have

A 450mm GT2-2 gear would have more like 706 +/- teeth. A 450mm GT2-5 gear would have 282 +/- teeth. A 450mm GT2-8 gear would have 169 +/- teeth.

Can approximate the number of teeth by dividing 1/2 the pitch by the radius, for a GT2-2: 1/225 = .0044444 (sin of the half angle)

Then take the arcsin: arcsin(.00444444) = .254648 Deg/half tooth

Multiple by 2 for central angle of each tooth: 2 x 0.254648 = 0.5092974 deg/tooth

Divide 360 deg by deg/tooth: 360/0.5092974 = 706.85615 teeth

Since there must be an whole number of teeth and we normally want the number to be even, round to 706 teeth with an approximate outside diameter of 450mm.

I think the match is correct, used to do this kind of thing for a living but now we just make choo-choo parts and the little marks on a tape maesure are all we need.

nitewatchman

nitewatchman wrote:

Flateric wrote: (BTW your avatar just alarms me for some reason, LOL)

Just a picture of a good ol southern boy.

I grew up in a region where you went to a family reunion to pick up chicks!

nitewatchman

Your good ol southern boy looks like he could bite the head off of an alligator.
He should learn how to smile not scowl.